This invention relates to an audio playback apparatus for an audio data source, such as a compact disk ("CD") which contains, in a standardized data format, audio information that is read, decoded, and separated into the individual signal components. The further processing circuitry, such as tone and volume control circuits, is generally located in a separate output amplifier but may also be contained in the audio playback apparatus, particularly if the latter is a small, portable pocket device for example. The data read from the CD, or other source for that matter is fed to an input decoder which performs an error correction by means of an error-checking code and feeds the corrected data stream to an output decoder which separates the data stream into the respective audio signal components, such as the left and right signals.
It is to be recognized that the audio data source is not limited to the CD mode, as other audio data sources are known whose data are delivered in a standardized data format. Such audio data sources can be accessed via the Internet, for example.
At the receiver end, this data is then stored on the hard disk in the PC or on any other suitable device, for example, an external or removable data carrier. CDs are reasonably priced devices for storing audio data, which have gained additional attraction by being rewritable ("burning"). To permit the use of commercially available audio playback apparatus, the data must be stored according to submitted standards, for example according to the "Sony-Philips Red/Blue Book".
The transmission, storage, and reproduction of audio data in accordance with these standardized data formats is very common. However, it has the disadvantage that these data formats do not provide for data compression and, at least in this respect, are inferior to more recent methods. There are methods in which the level of compression can be chosen in a wide range. Pure voice applications allow a higher compression level than high-quality music reproduction. Such a compression and coding method is known by the acronym "MPEG". The existing data compression methods should be utilizable during recording and reproduction without any basic changes having to be made to the system. For example, a CD player is desirable which can play back conventional audio CDs, CDs with source-coded data, and mixed-code CDs.
It is therefore a main object of the invention to improve an audio playback apparatus in such a way that it can process audio information which is assigned to different standardized data formats, and particularly audio information which also permits data compression.
Related objects of the invention are to provide a suitable storage device and an associated programming device for an audio playback apparatus in accordance with the invention.